Sealing means for electric switches



Aug. 14, 1956 H. HULTS SEALING MEANS FCR ELECTRIC SWITCHES Filed Aug.l2, 1955 ifilaire 'i States Patent O SEALING MEANS EUR ELECTRIC SWITCHESHarold W. Hults, Milwaukee, Wis., assignor to Cutler- Hammer, Inc.,Milwaukee, Wis., a corporation of Delaware Application August 12, 1953,Serial No. 373,339

3 Claims. (Cl. 20G-168) This invention relates to sealing means forelectric switches. It relates particularly to sealing means for actuatoropenings in switch casings.

A primary object of the invention is to provide effective, easilyassembled and low cost sealing means for electric switches.

Another object is to provide a seal for actuator openings in switchcasings which will permit easy and proper operation of the switchactuator.

Another object is to provide a compact but effective seal for actuatoropenings in electric switches.

Other objects and advantages of the invention will hereinafter appear.

The accompanying drawings illustrate an embodiment of the inventionwhich will now be described, it being understood that the invention issusceptible of embodiment in other forms, and that various modiiicationsmay be made in respect of structural details of the device illustratedwithout departing from the scope of the appended claims.

In the drawings, Figure l is a vertical crosssectional view of anelectric switch embodying the invention, certain of the parts beingshown in elevation;

Fig. 2 is a fragmentary vertical sectional view, at right angles to theview of Fig. 1, with certain portions shown in elevation; and

Fig. 3 is a cross-sectional view of a preferred form of the sealingmember employed, shown in normal or relaxed condition.

Referring to the drawings, the electric switch shown includes a casingconsisting of a box-like insulating base 10, a cover plate 12 overlyingthe top of the base 10 and a punched and stamped sheet metal switchframe 14 overlying the cover plate 12 and having portions thereof bentinto clamping engagement with inwardly and upwardly angled shouldersformed in the outer surfaces of the end walls of base 10.

The switch mechanism comprises a fixed, common terminal assembly 16secured at the mid-point of the length of the bottom wall of the base10, iixed terminal assemblies 18 and 20 secured to the bottom wall ofbase on opposite sides of the common terminal assembly 16, arocking-type bridging contactor 22, a bridging contactor operatingfinger 24 and an actuator 26. Each of terminal assemblies 18 and 2Gincludes a lug which is riveted to the underside of the bottom wall ofthe base 10. The rivet head is seated against the inner surface of thebottom wall of the base 10 and serves as a stationary contact tip. Thecommon terminal assembly 16 includes a U-shaped pivot member 1.6a and alug 16b which are electrically interconnected and secured to the upperand lower surfaces, respectively, of the bottom wall of base 10 by arivet 16C. 'Ihe upwardly extending arms of the U-shaped member 16a areslotted to accommodate the bridging contactor 22 and to provide a doublepivot for the latter; said contactor having laterally extending lugslocated between said upwardly extending arms of member 16a to preventsubstantial eudwise disref-v Y if placement of said contactor uponrocking or tilting thereof one of said lugs being shown at 22a in Fig.l.

The bridging contactor operating plunger 24 is slidably disposed in arecess 28 in the actuator 26. The plunger 24 is provided with a recess30 and is biased into engagement with the bridging contactor 22 by acoiled compression spring 32. The latter is held under compressionbetween the top of recess 28 and the bottom of recess 30.

The mounting bushing and operating mechanism for the switch includes anexternally threaded bushing 40 having an axial opening 40b therethrough,an operating lever 42 which is preferably formed of metal, a pivotmember 44 for the operating lever 42, a sealing member 46, and a pair oflike return springs 48 and 50 of known form.

The upper central portion 14a of the switch frame 14 is offsetvertically from the cover plate 12. 'I'his oifset portion is providedwith an opening 52. The lower end of bushing 40 has an enlarged insidediameter and a reduced outside diameter and extends through opening 52.The relatively thin extreme lower end portion of bushing 4i? is upsetradially outwardly or riveted over the lower surface of portion 14a toeffect a rigid and nonrotatable connection between the bushing 40 andthe switch frame 14. The operating lever 42 consists of a somewhatenlarged, generally spherical portion 54 disposed within the axialopening 40b of the bushing 40; and an operating handle portion 56 formedintegrally with and extending upwardly from the spherical portion 54 andoutwardly beyond the bushing 40; and an integral shank portion 58 whichextends downwardly from the spherical portion 54 through opening 52 anda relatively large opening 12a in cover plate 12 and is connected at itslower end to the top of actuator 26.

The headed pivot pin 44 penetrates openings in the walls of bushing 4t)and extends through the center of the spherical portion 54 of lever 42in a direction to provide for pivotal movement of the lever 42 in theplane of movement of bridging contactor 22; the opposite end of pin 44being upset, as shown in Fig. 2. Return springs 48 and 50 are trappedwithin the offset portion 14a of switch frame 14 on opposite sides ofthe shank 58 and said springs respectively act individually to normallybias the lever 42 from one of its on positions toward its central,upright or off position. If desired, of course, either or both of thesprings 48 and 50 may be omitted, if a momentary contact type of switchactuation is not required.

The sealing member 46 is composed of elastic, rubberlike material. It issubstantially cylindrical and has an axial opening therethrough. In itsrelaxed state the outside diameter of member is substantially greaterthan the diameter of the axial opening 49h in bushing 40. Theintermediate portion 46a of the axial opening in the sealing member 46is of a shape corresponding to the middle frustum of a sphere. Thedimensions of intermediate portion 4ta are substantially less than theoutside dimensions of the portion 54 of lever 42.

When in assembled relation with the switch bushing and operatingmechanism, the sealing member 46 is interposed between the bushing 46and the portion 54 of lever 42. Said sealing member surrounds and hugsor elastically embraces portion 54 and the opposite end portions 46b and46 of its outer peripheral wall are compressively engaged with aperipheral portion of the cylindrical wall of said opening 40h inbushing 40. The ends 46d and 46e of the axial opening in sealing member46 are each enlarged in an outward direction to provide clearancebetween said sealing member 46 and the portions of lever 42 on oppositesides of the portion 54 of lever 42. The ends of sealing member 46 arefree to alternative a relatively wide groove might be providedl intheinner wall 40b of the bushing 40.

These structural features permit a substantial amount; of` bulging ordistortion of the sealingA member 46 as theV lever is operated withoutmaterial increase in theforce required to. oper-ate the lever eventhough the sealgreef or"V4 compression. Moreover, the sphericalportion-541is relatively free to rotate with respect to-the sealingmemberthelever is` operated.

I' prefer-'to formY the sealing member 46` without perforations toaccommodate the pivot member 44. After the lever l2-and the sealingmember 45Y are placed in assembled relationship within bushing 40, thesealing member is piercexlV as the pivot pin 44 is inserted intoopenings providedfor it in thelever 42 and inthe Walls of-'the bushing40; the' piercing endy of pin 44 beingfthenl upset, as shown in Figi 2.

I` claim:

l". In an electric switch, in combination, amountingbushing memberhaving an axial opening therethrough of cylindrical form, an operatinglever having a generallyl sperical portiontdispose'dwithinA the openingin saidbushing member, a-y substantially cylindrical elastic sealingmember having an outside diameter normally greater-l than'the insidediameter of the peripheral wall of said bushing opening, said elasticsealing member havingan axialopening therethrough o-fnormally smallerdimensions than the outside dimensions of the sperical portionof-y theoperating lever, one of said members having formedV therein an annularperipheral` groove, said elastic sealingmember elastically embracingsaid sperical portion of said-V lever and extending axially of saidlever the length of said spericalv portion and being compressivelyengaged attheouter periphery thereof and on opposite sides of-saidlannular groove bushing opening, and a pivot member extending throughsaid' elastic sealing member and said spherical portion of the lever andabout which pivot member the lever' may be pivotally movedl with respectto said. bushing.

2. In an electric switch, in combination, a mounting* bushing having. anaxial opening therethrough, `an operatinglever having a generallyspherical portion disposed within the opening in said bushing, acylindrical elasticV sealing member substantially as long as thediameterof. said.' spherical portion of'the lever, said elastic sealingwith the peripheral wall of said member having an outside diameternormally greater than-thediameter of said bushing opening and having an.axial opening therethrough of normally smaller dimensions than theoutside dimensions of the sperical portion ofthe operating lever, saidelastic sealing member elastically embracing said sperical portion ofsaid lever and being compressively engaged at the outer peripherythereof with; the peripheral wall of said bushing opening, a

"L pivot member extending through said elastic sealing member and said:spherical portion of'thelever andraboutz which member said levermay bepivotally moved with respect to said bushing while insuring a sealedrelationship therebetween,y said elastic sealing member being proingmember is maintained under a relativelyl high de-` nl vided with anannular external recess between the upper and lower ends thereof, andsaid sealing member being free to bulge at said recess and to bulgeaxially of the opening in said bushing as said lever is pivotally movedrelatively to said bushing.

3. In anv electric switch, in combination, a mounting bushing having anaxial opening therethrough, an operating lever having a generallyspherical portion disposed within the opening in said bushing, acylindrical elastic sealing member substantially as long as the-diameterof said sperical portion of the lever, said elastic sealingmember'having an outside diameter normally greater thany thediameter ofsaid bushing opening and' having an axial opening therethrough ofnormally smaller dimensions than the outsidedimensions ofthe spericalportion of the operating lever, said elastic sealing memberelasticall'yV embracing-said' spherical portion of said lever and'beingVcompressively engaged at the outer periphery thereofl with theperipheral wall of said bushing opening, a pivot member extendingthrough said elastic sealing member andlsaid sperical portion of thelever' and about which member'said lever may be pivotally moved `withrespect to said' bushing while insuring a sealed relationshiptherebetween, said elastic sealing member being provided with an annularexternal recess between the upper and' lower ends thereof, and saidspherical portion of said lever' being relatively free to rotate withrespect to said sealing member as the latter isV bulged as an inci dentto pivotal movement of said lever with respect to said` bushing.

References Cited in the file of thisvpatent UNITED STATES PATENTS'2,400,845A Stearns May 21, 19,46

2,650,964 Razdow: Sept.v 1,1953?- FOREIGN PATENTS 9,744 Great BritainApr- 28,1904I

